Prop Strike 1973 Johnson 85HP

[Randyg123]

I read that, "Any impact caused by hitting an underwater object is absorbed by the propeller hub" Which I assume means no sheer pin on my motor.

So I am not sure exactly what will happen if I hit an underwater object with the prop. I've never taken the prop off myself so I've never looked at the assembly.

 

[5150abf]

Re: Prop Strike 1973 Johnson 85HP

most props are actually 3 pieces, the blades, a rubber bushing and the drive splines that go on the prop shaft.
In theory the rubber between the splines and prop absorb some of the impact and the blades bending /breaking take some but it still shocks the drive train.
One prop strike won't hurt anything unless it is really big, you get problems when you consistently hit things, it puts small cracks in the gears or clutchdog over time until they let go at full throttle, on my 3rd lower from river fishing,all let go at full throttle in deep water(highest stress)
SO unless you have a major prop strike you are probably okay if you clip a rock or something once or twice.
The best advice is to watch your depth gage and trim up when it is shallow, if you run your boat you will hit something eventually, it is part boating.

 

[Randyg123]

Re: Prop Strike 1973 Johnson 85HP

most props are actually 3 pieces, the blades, a rubber bushing and the drive splines that go on the prop shaft.
In theory the rubber between the splines and prop absorb some of the impact and the blades bending /breaking take some but it still shocks the drive train.
One prop strike won't hurt anything unless it is really big, you get problems when you consistently hit things, it puts small cracks in the gears or clutchdog over time until they let go at full throttle, on my 3rd lower from river fishing,all let go at full throttle in deep water(highest stress)
SO unless you have a major prop strike you are probably okay if you clip a rock or something once or twice.
The best advice is to watch your depth gage and trim up when it is shallow, if you run your boat you will hit something eventually, it is part boating.

Thanks for the information. Doesn't make sense to me not to have something that sacrifices like a shear pin but then I guess slippage becomes an issue with higher torque. I guess if I keep it on the trailer, all will be fine